FIG. 6 is a perspective view illustrating a conventional chip-type aluminum electrolytic capacitor of this type. Metal case 11 has a cylindrical shape having a bottom and stores a capacitor element (not shown). An open end of metal case 11 is sealed by a sealing member (not shown). Drawn section 12 is provided in metal case 11 when the sealing member is sealed. Insulated terminal plate 13 is attached to metal case 11 so as to be abutted with the sealing member. Insulated terminal plate 13 includes a hole (not shown) to which lead wires 14 introduced from the capacitor element are inserted. In order to store lead wires 14 inserted to the hole while lead wires 14 being orthogonally bent, groove section 15 is provided at an outer surface (bottom face in FIG. 6) of insulated terminal plate 13. The structure as described above can allow the capacitor to be surface-mounted to a printed substrate (not shown).
When the above chip-type aluminum electrolytic capacitor is used for an electric circuit, the chip-type aluminum electrolytic capacitor is required to have a predetermined vibration resistance when the chip-type aluminum electrolytic capacitor is surface-mounted. Thus, a side face of insulated terminal plate 13 is extended to provide a side wall section to support metal case 11 having a cylindrical shape having a bottom.
It is noted that known related art regarding the technique of this application includes, for example, Japanese Patent Application No. H09-162077 and Japanese Patent Application No. H11-233384.
In the above conventional chip-type aluminum electrolytic capacitor, lead wire 14 exposed from insulated terminal plate 13 has small volume and surface area. Thus, when lead wire 14 is solder-mounted to insulated terminal plate 13 by reflow on the printed substrate (not shown), lead wire 14 must be heated to a reflow temperature of insulated terminal plate 13. When insulated terminal plate 13 is heated to the reflow temperature, disadvantages are caused where not only an increased temperature of the capacitor body but also significant heat stress to other components mounted to the printed substrate are caused.
With regards to a trend for a reflow temperature for solder mount, lead-free solder having a high melting point has been used from a viewpoint of the recent global environment conservation and a solder mount with a further higher reflow temperature has been required.
In FIG. 7, the conventional chip-type aluminum electrolytic capacitor having the structure shown in the perspective view of FIG. 6 is applied with vibration stress in the shown directions for a vibration test. As shown in FIG. 7, when strong vibration stress is applied to the chip-type aluminum electrolytic capacitor in direction Y orthogonal to direction X along which lead wires 14 are connected, the capacitor body pendulates because the capacitor is joined to the substrate at two positions by lead wires 14. It is noted that direction Z shows an up-and-down direction of the capacitor body. Thus, soldered parts of lead wire 14 and the substrate and a root of lead wire 14 are damaged to cause a risk where the soldered parts may peel and lead wire 14 may be damaged or broken.